Darryl,
It's easy to isolate the trouble. Ride the bike and get the symptom to show it's face. When the brake is hot and dragging, open the bleeder. If the brake releases, the trouble is not the caliper, but something else blocking the fluid from return to the reservoir. Now, sometimes brake hoses collapse internally and keep fluid from returning to the master. Get it to happen again and open the line at the master cylinder end. Again, if the brake releases, the trouble is further up stream, (master or lack of free-play as has been suggested). If it does not, you need a hose.